In industry, it is very often desirable to have an amplifier capable of producing a large amount of output power, typically in the range of several kilowatts. An example of where this output power is required would be in the field of AM radio where large amplifiers are used for transmitter modules. A problem associated with such large amplifiers is the generally poor efficiency of the amplifier which increases the amplifier operating cost and construction cost. This problem has been addressed in my U.S. Pat. No. 4,788,452 which discloses a power supply having voltage sources which may be switched from parallel to series with other voltage sources upon the required amplifier output increasing over a predetermined maximum. When the required voltage falls below a predetermined maximum, the voltage source is switched back into a parallel configuration with the other voltage sources to improve cooling and power dissipation of the amplifier thus increasing efficiency.
This solution is satisfactory for applications requiring only a few separate voltage levels. However, this solution is not acceptable in applications where a plurality of voltage levels are required for even greater amplifier efficiency. Using the prior art switchable power supply described above a sixteen level power output would require sixteen separate voltage sources and fifteen switches. Obviously, such an amplifier construction would be cost prohibitive and of little practical value.